Amyotrophic lateral sclerosis: cell vulnerability or system vulnerability?
Version of Record online: 8 SEP 2013
© 2013 Anatomical Society
Journal of Anatomy
Special Issue: Motor Neurones and Diseases of Motor Neurones
Volume 224, Issue 1, pages 45–51, January 2014
How to Cite
Talbot, K. (2014), Amyotrophic lateral sclerosis: cell vulnerability or system vulnerability?. Journal of Anatomy, 224: 45–51. doi: 10.1111/joa.12107
- Issue online: 11 DEC 2013
- Version of Record online: 8 SEP 2013
- Manuscript Accepted: 10 AUG 2013
- MND Association
- amyotrophic lateral sclerosis;
- motor neuron disease;
Amyotrophic lateral sclerosis (ALS) is a complex neurodegenerative disease with clinical, pathological and genetic overlap with frontotemporal dementia (FTD). No longer viewed as one disease with a single unified cause, ALS is now considered to be a clinicopathological syndrome resulting from a complex convergence of genetic susceptibility, age-related loss of cellular homeostasis, and possible environmental influences. The rapid increase in recent years of the number of genes in which mutations have been associated with ALS has led to in vitro and in vivo models that have generated a wealth of data indicating disruption of specific biochemical pathways and sub-cellular compartments. Data implicating pathways including protein misfolding, mRNA splicing, oxidative stress, proteosome and mitochondrial dysfunction in the pathogenesis of ALS reinforce a disease model based on selective age-dependent vulnerability of a specific population of cells. To the clinical neurologist, however, ALS presents as a disease of focal onset and contiguous spread. Characteristic regional patterns of involvement and progression suggest that the disease does not proceed randomly but via a restricted number of anatomical pathways. These clinical observations combined with electrophysiological and brain-imaging studies underpin the concept of ALS at the macroscopic level as a ‘system degeneration’. This dichotomy between cellular and systems neurobiology raises the fundamental questions of what initiates the disease process in a specific anatomical site and how the disease is propagated. Is the essence of ALS a cell-to-cell transmission of pathology with, for example, a ‘prion-like’ mechanism, or does the cellular pathology follow degeneration of specific synaptic networks? Elucidating the interaction between cellular degeneration and system level degeneration will aid modeling of the disease in the earliest phases, improve the development of sensitive markers of disease progression and response to therapy, and expand our understanding of the biological basis of clinical and pathological heterogeneity.